1. Field of the Invention
The invention relates to a catheter device and, in particular, to a catheter device comprising a retentive catheter or short catheter.
2. Description of Related Art
There have been known short catheters comprising a cannula tube adapted to be introduced into the vein of a patient's arm while the connector at the rear end of the cannula tube is fixed to said arm. In the vicinity of the connector, there is provided an injection port through which fluid drugs may be administered to the patient.
The catheter device comprises a mandrin which is inserted through the connector into the cannula tube to block the cannula tube if no injection of medication or no infusion is made. If no injection is made through the catheter, the mandrin ensures that blood components are prevented from penetrating into the catheter and causing a thrombus formation. Further, the mandrin ensures that no contaminations may penetrate into the catheter and from there into the body of the patient.
The known short catheters are unsatisfactory because, prior to each injection, the mandrin must be removed in order to open the connection from the injection port to the cannula tube and to unblock the cannula tube. Upon termination of the injection, a sterilized new mandrin has to be introduced. In practice, the mandrin inserted is frequently the same as that removed from the retentive catheter prior to the injection. As evident, such handling is accompanied by a high risk of contamination. Moreover, such manipulations with the mandrin or mandrins are rather complicated for the user.
There has been known a catheter wherein the tube comprises a nonreturn valve at the proximal front end (German Patent No. 35 40 949). The valve stationarily mounted at the catheter tube is opened due to overpressure, but may not be used with an introduced mandrin.